This application claims the priority benefit of Taiwan application serial no. 90106701, filed Mar. 22, 2001.
1. Field of the Invention
The invention relates to a conveyance system. More particularly, the present invention relates to a circuit that detects the condition of circulation of the conveyor vehicles of a conveyance system.
2. Description of the Related Art
Conveyance system plays a substantial role in large manufactories that want to control their manufacturing time. If, for example, a conveyor vehicle that carries articles being manufactured from one processing station to another processing station inopportunely stops due to a disorder, it not only delays its time of delivery, but also the time of delivery of the other conveyor vehicles behind. As a result, the operation of each processing station through which the conveyor vehicles have to pass by to discharge the articles being manufactured is affected. The result is that the total manufacturing time of the final products and the time of delivery to the clients disadvantageously increase.
An aspect of the present invention is thus to provide a conveyor vehicle delay detecting circuit that can detect whether a conveyor vehicle has passed by predetermined locations in the conveyance passageway within a predetermined time interval. If a conveyor vehicle has not passed by one of the predetermined locations within the time interval, the present invention then activates a warning signal that alerts an operator of the delay of a conveyor vehicle. The operator thus can take immediate and adequate dispositions to recognize and repair the causes of the delay. The time interval of the disorder caused by the delay thus advantageously is reduced, which increases the efficiency of the conveyance system.
To attain the foregoing and other aspects of the present invention, a plurality of conveyor vehicle sensors are arranged at different locations of the circuit on which the conveyor vehicles circulate. A conveyor vehicle delay detection circuit connected to each of the sensors, according to a preferred embodiment of the present invention, comprises: a time counter circuit, a sensor receiver circuit, and an alarm circuit. A time interval is preset in the time counter circuit. If the time being counted by the time counter circuit exceeds the time interval preset in the time counter circuit while no vehicle has been sensed yet by one of the conveyor vehicle sensors, the time counter circuit outputs a delay signal to the alarm circuit. The alarm circuit then outputs a warning signal that activates an alarm device. The time counter circuit principally comprises a plurality of seven-segment monitors, a plurality of seven-segment latch/decode drivers, and a plurality of dual BCD up counters. The sensor receiver circuit principally comprises an operational amplifier, and the alarm circuit principally comprises a Hex buffer with high voltage open-collector outputs, a transistor, a relay device and an alarm device.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.